A variety of chain-type wrenches are well known, ranging from the relatively simple construction shown in the 1894 U.S. patent to Streeter et al, U.S. Pat. No. 520,712, to more complex designs as shown in U.S. Pat. Nos. 1,826,045 of 1931; 3,387,513 of 1968; and 3,505,914 of 1970.
Each of the tools described in the above noted patents are adapted to engage cylindrical members such as pipes within a range of diameters and exert a gripping force on the pipe as torque is imposed on the pipe. However, it has been found that when applied to a relatively fragile member such as the thin walled shell of a disposable, cannister-type oil filter, chain wrenches tend to crush the shell.
A variation of the conventional chain-type wrench is disclosed in U.S. Pat. No. 3,885,479 of 1975, wherein a series of pivotally interconnected, curved links are used instead of the more conventional chain construction. This design, while specifically described for removing oil filters, is obviously more expensive than a chain wrench and of course, is more restricted in the range of sizes it can accommodate.
U.S. Pat. No. 1,670,583 of 1928 discloses a clamp designed for removing jar tops, and includes a flexible metal band connected to one end of a jaw of a pair of pliers and carrying a chain which overlies a portion of the band and is attached to it at opposite ends of the chain. The other jaw of the pliers carries a hook which is engageable with the chain so that when the handles of the pliers are squeezed together a jar top may be gripped by the band.
With this construction it will be apparent that the gripping force exerted on the jar top is dependent upon the force applied to the plier handles, and the smooth inner surface of the band will tend to slip about the jar top if insufficient force is applied to the plier handles. Additionally, the cost of this type of construction will obviously be greater than that of more conventional chain-type wrenches.